The post-fire response of an obligate seeding Triodia species (Poaceae) in the fire-prone Kimberley, north-west Australia

Abstract

Triodia spp. have been described as behaving functionally as a shrub because above ground biomass accumulates slowly over time culminating as the dominant vegetation layer. When combined with high flammability, little seed dormancy and conflicting evidence for fire induced seed germination, obligate seeding species may be more vulnerable to short fire intervals than resprouting species. This study investigated the post-fire regeneration response of the obligate seeder Triodia sp. nov. (aff. T. schinzii Henrard) in the fire prone Kimberley, Western Australia. Adult plants were destroyed by fire in experimental plots to assess the degree of regeneration from either resprouting or germination from seed due to fire. To control for the removal of adults, without fire, plants were pulled out by hand in replicate plots. Germination of Triodia sp. nov. seed from the soil seed bank was strongly induced by fire. Establishment and survival of seedlings through the first dry season was high with a small proportion of individuals flowering at this time. It is concluded that Triodia sp. nov. is resilient to the short fire intervals experienced in the Kimberley where it is a successful localised species.